The present invention relates generally to turbines including windturbines, which are commonly called "windmills" in prior patent documents, and relates more particularly to turbines such as windmills with variable pitch vanes.
If the axis of a wind powered turbine, or windmill, is not parallel to the direction of the wind but is perpendicular to it, the vanes rotating about the axis move into the wind and then away from it. So that the forces acting on the vanes, caused by the wind, do not counteract each other, variable pitch vanes have been devised. They allow the wind to act on a large area of the vane when the wind force is in the direction of rotation, and reduce the area of the vane effectively acted on by the wind when the wind force would be opposite the direction of rotation. The torque forces created by such devices are unfortunately uneven and the machines consequently cumbersome and inefficient. Examples of such devices are shown in U.S. Pat. Nos.
177,057--5/9/1876 PA1 250,806--12/13/1881 PA1 862,299--8/6/07 PA1 993,120--5/23/11 PA1 1,154,930--9/28/15 PA1 1,249,206--12/4/17 PA1 3,093,194--6/11/63
Accordingly, it is an important purpose or object of this invention to provide a turbine such as a windmill with characteristics superior to other variable pitch windmills. It is an object to provide a fluid turbine such as a windmill with more uniform and more effective torque, one that develops less vibration and more power for a given size.